Textile size

ABSTRACT

THE PRESENT INVENTION RELATES TO A COPOLYMER OF (A) ACRYLIC ACID AND (B) AN ACRYLATE SELECTED FROM THE CLASS CONSISTING OF SODIUM, POTASSIUM AND AMMONIUM ACRYLATES, THE MOLAR OF RATIO OF (A) AND (B) BEING FROM 1:0.3 TO 1:6 AND A 5% WEIGHT AQUEOUS SOLUTION OF THE COPOLYMER AT 20* C. HAVING A PH OF 4.0 TO 6.5 AND A VISCOSITY AS MEASURED BY A BROOKFIELD VISCOMETER BETWEEN 20 CPS. WHEN MEASURED USING A NO. 1 SPINDLE AND 4000 CPS. WHEN MEASURED USING A NO. 6 SPINDLE, THE SPINDLE SPEED IN BOTH CASES BEING 100 R.P.M. IT ALSO RELATES TO AQUEOUS SOLUTIONS OF SUCH COPOLYMERS AND THEIR USE AS SIZES FOR STAPLE YARNS.

United States Patent U.S. Cl. 117-138.8 F 7 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a copolymer of (a) acrylic acid and (b) an acrylate selected from the class consisting of sodium, potassium and ammonium acrylates, the molar ratio of (a) and (b) being from 1:0.3 to 1:6 and a 5% weight aqueous solution of the copolymer at 20 C. having a pH of 4.0 to 6.5 and a viscosity as measured by a Brookfield viscometer between 20 cps. when measured using a No. 1 spindle and 4000 cps. when measured using a No. 6 spindle, the Spindle speed in both cases being 100 rpm. It also relates to aqueous solutions of such copolymers and their use as sizes for staple yarns.

usually film-forming adhesive resins.

Water-soluble or water-dispersible colloids of natural origin such as starches, gums, glues and the like materials have been used and continue to be used for this purpose. Such materials, however, have the disadvantage that relatively large quantities, commonly exceeding 12% on the Weight of the yarn, are required for effective sizing. Further, such materials require special processes for their removal from the woven fabric, such as enzyme desizing. The quantities used also contribute adversely to the Weight and volume of the yarn on the packages.

Furthermore such materials show little adhesion to hydrophobic fibres such as polyester, polyamide and polyacrylonitrile and for sizing continuous filament yarns produced from these fibres it has been necessary to develop synthetic polymers having specific adhesion characteristics appropriate for a particular fibre type. Thus continuous filament polyester yarns may be woven satisfactorily using as sizes acrylic or vinyl ester copolymers containing minor proportions, commonly less than 30 mol percent of a carboxylic monomer. Likewise polyamide continuous filament yarns may be woven satisfactorily using sizes comprising polyvinyl alcohol or homopolymers of acrylic acid.

On the other hand staple yarns are much more irregular in surface geometry and in tensile properties and hence give rise to weaving difiiculties which are not found with continuous filament yarns and it is a fact that those synthetic sizes which have been developed and found satisfactory for continuous filament yarns have not found economic application for staple yarns.

It has been proposed to size continuous filament or staple yarns of a great variety of types by employing co- 3,711,323 Patented Jan. 16, 1973 polymers which contain carboxyl and nitrile groups in a molar ratio of 0.321 to 0.075 :1, the carboxyl groups being either free or combined with sodium, potassium or ammonium ions. However the sizing effect obtainable at economic addition levels is not always adequate and it has been emphasized that it is important to remain within the above molar ratios.

It has also been proposed to size staple yarns containing cellulosic and/or acrylic fibres in a weight ratio of at least 30%, by employing copolymers of (a) acrylonitrile and (b) acrylic acid and its sodium or ammonium salt wherein the polymer contains units of (a) and (b) in the molar ratio of from 1:1.5 to 1:7.

We have now found sizes that are. particularly suitable for application to staple yarns which are constituted of either hydrophobic fibres or cellulosic fibres or blends of the two types and the products of the invention gi-ve considerably improved weaving performances at relatively low levels of ap lication and furthermore are capable of being removed Where this is necessary, by extremely simple scouring methods.

It is of particular value that the products of the invention will effectively size staple yarns produced entirely from polyester fibre or entirely from acrylic fibre or entirely from cellulosic fibres or blends of these fibres, hence it is possible at one weaving shed to utilise a single product for all weaving programmes with only minor variations in size bath formulation.

According to the present invention a size is provided which comprises a copolymer of (a) acrylic acid and (b) sodium, ammonium or potassium acrylate, the molar ratio of (a) and (b) being from 110.3 to 1:6, preferably from 1:08 to 122.6, and a 5% by weight aqueous solution of the co-polymer at 20 C. having a pH of 4.0 to 6.5 and a viscosity as measured by a Brookfield viscometer between 20 cps. when measured using a No. 1 spindle and 4,000 cps. when measured using a No. 6 spindle, the spindle speed in both cases being rpm.

The invention also includes a size comprising an aqueous solution of said copolymer.

The invention further includes a process of sizing staple yarns by applying this aqueous solution to the yarn and then drying the yarn thus treated, the amount of solution being such that there is at least 1% by weight of solid polymer on the yarn.

The invention also includes yarns thus 'sized.

The sizes of the present invention are more effective than those at present in use in that there is less yarn breakage and moreover these sizes are readily removable and render hydrophobic textile yarns more amendable to subsequent textile processing.

Yarns that can be sized according to the invention inelude, for example, those of polyester fibres or poly- I acrylic fibres or natural and/or regenerated cellulose fibres The polymers can be applied as sizes either in the form obtained in manufacture or after dilution. However, they can also be converted to a powder and dissolved in water before use.

The solutions employed in accordance with the process of this invention preferably contain 0.5 to 20 percent by weight of polymer. The following concentrations have proved to be particularly satisfactory: l to 8 for cotton, 4 to 10 for linen, l to 5 for viscose rayon, and 3 to percent by weight for polyester staple fibre.

In addition to the polymers mentioned, the solutions according to the invention can contain conventional sizing agents and/or sizing auxiliaries, e.g. natural starches, chemically modified starches, polyvinyl alcohol, and fats or waxes.

The polymer solution may be applied to the substrate on machines that are well known in the industry at a temperature of from 50 C. to 80 C. Suitable machines are open width warp sizing machines, single end sizing machines, package sizing machines or sizing sprays.

In the following examples laboratory testing of the yarns was carried out under standard conditions of 65 percent relative humidity at 20 C. whereas field trials were carried out under the conditions prevailing at individual installations.

Abrasion resistance was measured dynamically by abrading test specimens against a reciprocating head. The abrasion factor is the number of reciprocations of an abrading machine required to rupture one thread from a group of fifty threads, when the abrading machine is reciprocating at 300 r.p.m. and the yarn speed through the abrasion zone is cm./ min.

Tensile properties of yarn specimens were measured on a Cambridge Textile Extensometer, and are expressed as (1) stress-breaking load in gms., and (2) strainpercentage extension at break.

EXAMPLE 1 50 threads of a 1/37s Tex Egyptian cotton yarn were treated on a Callaway Slasher with the following liquors applied at 60 C:

1(a) 3 percent aqueous solution of a commercially available, salt free sodium carboxymethylcellulose,

1(b) 3 percent aqueous solution of a polymer containing acrylic acid and sodium acrylate in a molar ratio of 1:6. A 5 percent solution had a viscosity of 60 cps. at 25 C. and a pH of value 6.5

1(a) 3 percent aqueous solution of a polymer containing acrylic acid and sodium acrylate in a molar ratio of 1:03. A 5 percent solution had a viscosity of cps. at C. and a pH value of 4.0.

1(d) 3 percent aqueous solution of a polymer containing acrylic acid and sodium acrylate in a molar ratio of 1:6. A 5 percent solution had a viscosity of 4000 cps. at 25 C. and a pH value of 6.5.

1(e) 3 percent aqueous solution of a polymer containing acrylic acid and sodium acrylate in a molar ratio of 1:03. A 5 percent solution had a viscosity of 650 cps. at 25 C. and a pH value of 4.0.

The treated yarns, together with an untreated yarn,

were conditioned for 48 hours at 65% relative humidity and 20 C. before carrying out the abrasion test. The values presented in the following table were obtained.

An abrasion factor of 10 10 or greater at 5 gms. tension is known to give acceptable weaving conditions and 'it is well known in the art that a size add-on of 5% sodium carboxy methyl cellulose will cause an average quality 1/37s Tex Egyptian cotton yarn to weave satisfactorily.

The factors presented in the above table show that a considerable improvement in abrasion resistance is effected with liquors 1(b) 1(0) 1(d) 1(e).

EXAMPLE 2 Per- Abrasion factor cent add- 6 grams on tension Stress IOgrams (grams! Strain tension thread) (percent Untreated (1) 0. 9x10 0. 2x10 '2, 145 s Treated (I 4. 7 10 10 5. 4x10 2, 560 5. 7

Untreated (11).. 0. 7x10 0.1)(10 1,859 5. 2

Treated (II) 10x10 6. 5x10 2,218 5. 0

EXAMPLE 3 Two 4,000 yards long warps containing 3328 threads of 1/37s Tex cotton yarn were sized under identical conditions on a 9 cylinder industrial sizing machine. A Shirley Automatic Size Box was used to control the weight of liquor which was applied to the yarn.

Liquor 3.( a)

250 parts wheat flour 100 parts maize starch 30 parts tallow 2 parts soft soap -1 part of a fungicide such as Shirlan (Shirlan is the Registered Trademark of Shirley Developments Ltd.)

2117 parts water i I The ingredients were slurried in water and boiled for 1 hour before applying at a temperature of 95 C. The- Shirley Automatic Size Box was set to apply 14 percent dry size to the cotton yarn.

Liquor 3(b). 6 percent aqueous solution of equimolar amounts of acrylic acid and sodium acrylate, a 5 per-- cent solution having a viscosity of 3960 cps. at 25 C. and a pH value of 5.2.

The temperature of this liquor was raised to 90 C. before application and the Shirley Automatic Size ,Box set to apply 6% of dry size to the cotton yarn.

Both the above warps were woven on similar looms: under identical conditions. The warp sized with liquor 3(a) had an average of 3.6 broken ends per 100,000 picks,- whereas the warp sized with liquor 3(b) had an average of 0.5 broken end per 100,000 picks.

EXAMPLE 4 13,000 yards long warps containing 3664 threads of 1/50s Tex viscose rayon/nylon (:15) yarn were sized from a 3 percent aqueous solution of a copolymer comprising equi-molar amounts of acrylic acid and sodium acrylate, a 5 percent solution having a viscosity of 3960 cps. at 25 C. and a pH value of 5.2.

The solution was applied at a temperature of 95 C. on a 9 cylinder industrial sizing machine.

The sized yarns were woven under practical mill conditions and had an average of 2.8 warp breaks per 100,000 picks.

Similar yarns sized with 8 percent (on weight of yarn) starch ether size, regularly have an average of 4.0 warp breaks per 100,000 picks.

EXAMPLE 5 Four 2,000 yards long warps containing 5920 threads of 1/30s Tex polyester/ cotton (67:33) yarn were sized on a 11 cylinder industrial sizing machine which had facilities for a two stage application technique which is known in the trade as double box sizing.

The following liquors were used:

Liquor 5 (a): 8 percent aqueous solution of a copolymer comprising equimolar amounts of acrylic acid and sodium acrylate, a 5 percent solution having a viscosity of 3960 cps. at 25 C. and a pH value of 5.2.

Liquor 5 (b):

14 parts starch ether 1 part sodium carboxymethylcellulose 1 part tallow 84 parts water Liquor 5(c): 12 percent aqueous solution of a copolymer comprising equimolar amounts of acrylic acid and sodium acrylate, a 5 percent solution having a viscosity of 30 cps. at 25 C. and a pH value of 5.2. Liquor 6(d):

8 parts starch ether 2 parts sodium carboxymethyl cellulose 1 part emulsified tallow 89 parts water Liquor 6(e):

38 parts liquor 5(a) 11 parts starch ether 1 part spermaceti 50 parts water Warp I was sized with liquor 5(a) at 98 C. and subsequent analysis indicated that 8 percent of dry size had been applied to the polyester/cotton yarn.

Warp II was sized with liquor 5 (b) at 98 C. and subsequent analysis indicated that 16.5 percent of dry size had been applied to the polyester/cotton yarn.

Warp III was sized with liquor 5(c) in the first size box, partially dried and further sized with liquor 5 (d) in the second size box. Both liquors were applied at 95 C. and subsequent analysis indicated that 9 percent of dry size had been applied from liquor 5(c) and that 9.5 percent of dry size had been applied from liquor 5 (d) to the polyester/ cotton yarn.

Warp IV was sized with liquor 5(e) at 90 C. and subsequent analysis indicated that 17.7 percent dry size had been applied to the polyester/ cotton yarn.

All four warps were lubricated on the sizing machine with a molten commercial wax.

The above warps were then woven in similar looms under identical conditions and the following warp breakage rates were obtained:

Warp I: 1.4 end breaks per 10,000 picks Warp II: 2.0 end breaks per 10,000 picks Warp III: 0.86 end break per 10,000 picks Warp IV: 1.06 end breaks per 10,000 picks.

EXAMPLE 6 A 1000 yds. long warp containing 3960 threads of 1/ 10s Tex 100% polyester fibre yarn was sized on a 2 cylinder industrial sizing machine with the following liquor at a temperature of 90 C.

value of 5.2 77 Spermaceti 5 Water 541 Total 700 Subsequent size on yarn determination (British Standard Test Method) indicated that a total of 19.4% size had been applied to the yarn. Weaving was carried out on a conventional shuttle loom fitted with six banks of drop wires and four staves of steel healds. The fabric was constructed in plain weave from 84 ends per inch and picks per inch of 1/ 10 Tex polyester yarn. The Warp breakage rate was 1.0 per 10,000 picks, an excellent result when compared with similar warps which were sized with 25% Oxidised Corn Starch and were found to be unweavable.

EXAMPLE 7 4 warps, each 2200 yds. long containing 3700 threads of l/ 8 Tex 100% acrylic fibre yarn were sized on a 9 cylinder industrial sizing machine with the following liquor applied at a temperature of 60 C.:

Parts Copolymer comprising equimolar amounts of arylic acid and sodium acrylate, a 5 percent solution having a viscosity of 3960 cps. at 25 C. and

a pH value of 5.2 5 Copolymer comprising equimolar amounts of acrylic acid and sodium acrylate, a 5% solution having a viscosity of 20 cps. at 25 C. and a pH value Tallow 1 Water 89 Total 100 Subsequent size on yarn determination (British Standard Test Method) indicated that a total of 11.2% size had been applied to the yarn. The yarn was woven in a conventional loom and the average number of warp breaks was 0.8 per 10,000 picks. Similar warps, which were sized with 20% Sago Flour had a warp breakage rate of 2.0 per 10,000 picks and were not considered to be commercially acceptable.

We claim:

1. A process of sizing staple yarns which comprises applying a size comprising an aqueous solution of a copolymer consisting of (a) acrylic acid and (b) an acrylate selected from the class consisting of sodium, potassium and ammonium acrylates, the molar ratio of (a) and b) being from 1:03 to 1:6 and a 5% weight aqueous solution of the copolymer at 20 C. having a pH of 4.0 to 6.5 and a viscosity as measured by a Brookfield viscometer between 20 cps. when measured :using a No. 1 spindle, and 4000 cps. when measured using a No. 6 spindle, the spindle speeds in both cases being 100 rpm, said aqueous solution containing 0.5 to 20% by weight of said copolymer and the amount of said aqueous solution being such that there is at least 1% by weight of solid copolymer on the yarn, and then drying the yarn thus treated.

2. A process as claimed in claim 1 in which the molar ratio of (a) and (b) in the copolymer is from 1:0.8 to 1:2.5.

3. A process as claimed in claim 1 in which the size also contains at least one compound selected from the class consisting of sizing agents.

4. A process as claimed in claim 1 in which the staple yarns are selected from the class consisting of cellulosic, polyester and polyacrylic staple yarns.

5. A process as claimed in claim 1 in which the staple yarns are selected from the class consisting of a mixture 7 8 of cellulosic and polyester staple yarns and a mixture 2,819,189 1/1958 Suen et al. 117145'X of cellulosic and acrylic staple yarns. 2,909,447 10/1959 Scott 117-445 X 6. The product of the process of claim 1. 2,646,412 7/1953 Bruner et al. 1l7'145 X 7.A process as claimed in claim 1 in which the size also contains at least one compound selected from the 5 WILLIAM D. MARTIN, Primary Examiner class consisting of sizing auxiliaries. HILD'S, A i t t E min r References Cited US, Cl. X R,

UNITED STATES PATENTS 10 117 13s.s N, 138.8 UA, 139.5 A, 143 A, 145; 260- 3,519,477 7/1970 Wolf et al. 117 14s X 29.6 H, 80.3

2,807,865 10/1957 Shippec ct al. ll7l38.8 X 

